Silkies, bones, and egg laying

[BuffaloChichinWings]

I'm wondering about "measuring" silkie/bantam chickens for laying. Of course I can't remember the bone names, but on standard size hens you can feel about 4 finger widths on the side and about 2 finger widths above the vent when they are laying and less when they aren't. Does anyone know the "measurements" of these bone widths on bantams?
I sure hope someone can understand me

 

[nuthatched]

Pelvic bones
It's probably similar for silkies.